xiv Introduction
The 20th century was rooted in the 19th century; the end of the American
Civil War (April 12, 1861–May 9, 1865) was only 35 years before the be-
ginning of the 20th century. The post–Civil War era was marked by the
rancor of the Reconstruction era, the claiming of Native American territo-
ries for settlement, and exploitation of labor by increasingly powerful cor-
porations. By 1917 when the United States entered World War I, a war
already starting its third year of European battles, the United States had
changed dramatically from its 1900 form. Its population had grown from
76.09 million in 1900 to 103.27 million in 1917, an increase of 27.18 mil-
lion; 14.5 million of those new residents arrived in the United States from
other countries in a massive immigrant influx. By the end of the 20th cen-
tury, the population in the United States was far more ethnically, racially,
and culturally diverse than it had been at the end of the 19th century. By
2002 for most Americans, national identity meant sharing cultural roots in
other parts of the world. These changes were not always embraced by U.S.
citizens; nativist groups in the early 20th century such as the Ku Klux
Klan argued that a racial and religious “purity” (white and Protestant)
should define the country. The Ku Klux Klan is one example of the reac-
tionary grassroots response; official acts of Congress restricting immigra-
tion, sanctioned by the U.S. Supreme Court, were formal expressions of
native-born Americans’ unease with the demographic shifts in the popula-
tion. In addition, the disenfranchisement of African Americans after the
defeat of Reconstruction in the late 19th century carried into the 20th cen-
tury via laws at the city, county, state, and federal levels that restricted the
political, economic, and even social activities of black people in the United
States. It wasn’t until after World War II that the National Association for
the Advancement of Colored People and other civil rights groups were
successful at attacking the formal and legal constraints placed on African
Americans.
The American economy became the dominant world economy early in
the 20th century. As the history textbook Who Built America? points out, by
1914 the U.S. per capita gross national product had increased by 50 percent
since 1896; this meant that in constant dollars, the United States was mak-
ing 50 percent more in dollar value per resident, an enormous increase
of economic output. By 1910 the United States was the most productive
economy in the world—a top position enabled by changes in how goods
were produced (such as factories that now built products on continuous-
production or assembly lines) and distributed (through the development
of nationally branded products and chain stores). This productivity did not
mean that all workers enjoyed the benefits equally: until quite late in the
century African Americans, other minorities, and women struggled with un-
equal pay and rights. Overall, though, the U.S. economy developed into a
global economic force, far outproducing many other nations.
